1. Field of the Invention
The present invention relates to a fluid separation filter, and relates particularly but not exclusively, to a fluid separation filter for removing water vapor from air.
2. Description of the Invention
Bundles of tubular members of porous material may be used to remove water vapor or other contaminants from an air flow. Water is adsorbed by the porous material constituting the tubular members as air flows through them. An example of this method of drying air is described in PCT publication number WO2009/053760. Attention is also to be drawn to WO2008/110820 which is directed towards the preparation and use of regenerable adsorption units and in particular regenerable hollow fibers and electrically regenerable fibers.
Once saturated with water porous tubular members may be regenerated and used to remove water vapor from more air. Regeneration is achieved by heating the porous tubular members thereby causing evaporation of the adsorbed water away there from. An electrical current may be used to heat such porous tubular members. Porous tubular members are first extruded as two layers of material, namely an inner adsorbent layer and an outer electrically conductive layer made from e.g. a mixture of copper and graphite, before a voltage is applied across them, causing a current to flow, thereby generating heat.
An evenly distributed flow of current through the porous tubular members in a bundle of such members is required in order to evenly regenerate each individual tubular member in the bundle. If more current flows through one porous tubular member than another, then such members will heat up to different temperatures the cooler of which will not regenerate as efficiently as the one which heats up the most. This reduces the air drying efficiency of a bundle of porous tubular members as a whole.
For example, an existing bundle has a current applied to it using a conducting resin that is used at either end of the bundle to seal the ends. A current is applied to the outside of the resin and current flows through the resin to the conductive coating on the fibers, and along this way to the more conductive region at the other end of the fibers, thereby generating heat in the fiber. However, differences in resistance result in different current flows through fiber coatings located within the bundle. Fiber at the center of the bundle receives less current and therefore heats up less. The problem with the prior art is that there exists no way of providing a substantially even flow of current through each individual tubular member in a bundle of such tubular members.
There further exists the problem of evenly applying potting compound between the fibers already assembled in a bundle.
Preferred embodiments of the present invention seek to overcome the above disadvantages of the prior art.